Mu Columbae is a star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 of Columba

Columba (constellation)

Columba is a small, faint constellation created in the late sixteenth century. Its name is Latin for dove. It is located just south of Canis Major and Lepus.-History:...

. It is one of the few O-class

Stellar classification

In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

 stars that is visible to the unaided eye. The star is known to lie approximately 1,300 light years from our solar system

Solar System

The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

 (with an error margin of a few hundred light years).

This is a relatively fast rotating star that completes a full revolution approximately every 1.5 days. (Compare this to our Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

, which at only 22% of this star's diameter rotates only once every 25.4 days.) This rate of rotation is fairly typical for stars of this class.

Based on measurements of proper motion

Proper motion

The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...

 and radial velocity

Radial velocity

Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

, astronomers know that this star and AE Aurigae

AE Aurigae

AE Aurigae is a runaway star in the constellation Auriga; it lights the Flaming Star Nebula.AE Aurigae is a blue O-type main sequence dwarf with a mean apparent magnitude of +5.99. It is classified as an Orion type variable star and its brightness varies irregularly between magnitudes +5.78 and...

 are moving away from each other at a relative velocity

Relative velocity

In non-relativistic kinematics, relative velocity is the vector difference between the velocities of two objects, as evaluated in terms of a single coordinate system....

 of over 200 km/s. Their common point of origin intersects with Iota Orionis

Iota Orionis

Iota Orionis is the brightest star in Orion's sword, and is located at the tip of the sword. It has the traditional names Hatsya , or in Arabic, Na’ir al Saif, which means simply "the Bright One of the Sword."+-9*Iota Orionis is a quadruple system dominated by a massive spectroscopic binary with an...

 in the Trapezium cluster

Trapezium (astronomy)

The Trapezium, or Orion Trapezium Cluster is a tight open cluster of stars in the heart of the Orion Nebula, in the constellation of Orion. It was discovered by Galileo Galilei. On February 4, 1617 he sketched three of the stars , but missed the surrounding nebulosity...

, some two and half million years in the past. The most likely scenario that could have created these runaway stars is a collision between two binary star

Binary star

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...

 systems, with the stars being ejected along different trajectories radial to the point of intersection.

Etymology

In Chinese astronomy

Chinese astronomy

Astronomy in China has a very long history, with historians considering that "they [the Chinese] were the most persistent and accurate observers of celestial phenomena anywhere in the world before the Arabs."...

, Mu Columbae is called 屎, Pinyin

Pinyin

Pinyin is the official system to transcribe Chinese characters into the Roman alphabet in China, Malaysia, Singapore and Taiwan. It is also often used to teach Mandarin Chinese and spell Chinese names in foreign publications and used as an input method to enter Chinese characters into...

: Shǐ, meaning Excrement, because this star is marking itself and stand alone in Excrement asterism, Three Stars

Three Stars (Chinese constellation)

The Three Stars mansion is one of the twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger. This collection of seven bright stars is visible during winter in the Northern Hemisphere .- Asterisms :...

 mansion (see : Chinese constellation

Chinese constellation

Chinese constellations are the way the ancient Chinese grouped the stars. They are very different from the modern IAU recognized constellations. This is because the IAU was based on Greco-Roman astronomy instead of Chinese astronomy....

). 屎 (Shǐ) westernized into She by R.H. Allen, with the meaning is "the Secretions"

This star, along with ζ CMa

Zeta Canis Majoris

Zeta Canis Majoris is a spectroscopic binary in the constellation Canis Major. It has the traditional name Furud or Phurud, from the Arabic ألفرد al-furud meaning the bright single ones or, perhaps by a transcriber's error, from Al Ḳurūd , the Apes, or Al Agribah , the Raven by Al...

, λ CMa

Lambda Canis Majoris

Lambda Canis Majoris is a star in the constellation Canis Major. This star, along with ζ CMa, γ Col, δ Col, θ Col, κ Col, λ Col, μ Col and ξ Col, were Al Ḳurūd , the Apes....

, γ Col

Gamma Columbae

Gamma Columbae is a blue subgiant star in the constellation Columba. It is approximately 854 light years from Earth. This star, along with ζ CMa, λ CMa, δ Col, θ Col, κ Col, λ Col, μ Col and ξ Col, were Al Ḳurūd , the Apes....

, δ Col

Delta Columbae

Delta Columbae is a spectroscopic binary yellow giant star in the constellation Columba. It has the uncommon traditional name Ghusn al Zaitun, from the Arabic الغصن الزيتون al-ghuşn al-zaitūn "the olive branch".....

, θ Col

Theta Columbae

Theta Columbae is a blue subgiant star in the constellation Columba.This star, along with ζ CMa, λ CMa, γ Col, δ Col, κ Col, λ Col, μ Col and ξ Col, were Al Ḳurūd , the Apes.....

, κ Col

Kappa Columbae

Kappa Columbae is a giant star in the constellation Columba.This star, along with ζ CMa, λ CMa, γ Col, δ Col, θ Col, λ Col, μ Col and ξ Col, were Al Ḳurūd , the Apes.....

, λ Col

Lambda Columbae

Lambda Columbae is a blue dwarf star in the constellation Columba. It is approximately 342 light years from Earth. This star, along with ζ CMa, λ CMa, γ Col, δ Col, θ Col, κ Col, μ Col and ξ Col, were Al Ḳurūd , the Apes....

 and ξ Col

Xi Columbae

Xi Columbae is a yellow-orange giant star in the constellation Columba. This star, along with ζ CMa, λ CMa, γ Col, δ Col, θ Col, κ Col, λ Col and μ Col, were Al Ḳurūd , the Apes.-References:#...

, were Al Ḳurūd (ألقرد - al-qird), the Apes.

External links

• Mu Columbae by Professor Jim Kaler.